Brake band



F. L. MUNROE Nov. 6, 1 934.

BRAKE BAND Filed Aug. 28, 1931 INVENTOR m 2W6,

Patented Nov. 6, I934 lioness earner BRAKE BAND Application August 28,

4 Claims.

This invention relates to a brake band particularly adapted for use in the textile industry in connection with brakes for looms although it is suitable for any use requiring frictional engagement with a smooth cooperating surface such as clutches, belts, transmission linings or the like.

Textile looms require an even greater degree of perfection in their braking systems than is required in other industries generally. The textile loom brake must cause an instantaneous cushioned stop. If the braking action is not instantaneous, the shuttle will not be retained in the shuttle box. This would necessitate a '1 troublesome and costly step, namely, that of working the shuttle back to the box by hand. It would also result in an imperfect fabric.

The use of cork in brake linings of various kinds has been suggested many times in the Ipast. However, these prior art constructions have never achieved any notable degree of success, particularly those suggested for the textile industry. The reasons for such failures are numerous. In some cases only inserts of cork 'were used, in which cases the surface area was generally too small to impart the required frictional effect. The cork inserts are less substantial than a continuous sheet of cork and are likely to crumble. The inserts also become loose and fall out of place easily. Cork strips cannot be used alone because of the impossibility of riveting cork to the brake shoe. In such cases it is necessary to secure the cork to the brake shoe by cement. This is a particularly expensive operation in View of the fact that it necessitates the dismantling of parts of the loom.

I have invented a brake band particularly adapted for use in textile loom brakes that is very efilcient in service, that presents a positive gripping surface, which stops the looms quickly but gently and which will hold the brake drum without any slippage. My brake bands are inexpensive, economical to Furthermore, in cases where the brake must be Ire-lined, the brake band can be riveted to the shoe as a unit with a minimum amount of trouble.

The drawing shows a longitudinal cross sec tional view of one of my brake bands. In the 'idrawing the reference numeral 1 indicates a layer of granulated cork densely compressed in composition form. The size of the cork granules may be varied but I prefer granules that are fine enough to pass through a screen having 10 meshes to the inch but not fine enough to pass use and will wear well.

1931, Serial No. 559,893

through a screen having 30 meshes to the inch. Any suitable binder may be used to secure the cork granules together. The mass may be com pressed to a volume between and 1/22 of the volume of the uncompressed mix. A backing 2 of vulcanized fiber is secured to the cork composition by any suitable cement. For this purpose I preferably use a casein glue. Cork slabs of suitable thickness are formed in large sheets. A layer of cement is applied on one surface of the cork and on one surface of a large sheet of vulcanized fiber. The two cemented surfaces are placed in contact with each other and a stack of such composite sheets is placed in a press. Suitable pressure is applied to cause the cork composition and vulcanized fiber to adhere firmly together. The pressed sheets are removed from the press and the brake bands are cut tow the desired size. The brake band is composed of a comparatively rigid backing of vulcanized fiber and a layer of granulated cork composition in which the granules of cork are cemented to each other and to the backing so that they are continuously supported by the backing over the entire area of the brake band.

The drying of the glue is accompanied by shrinkage which imparts to the brake band a natural curvature that makes a further shaping process unnecessary. This natural curvature facilitates application of the brake band to the brake shoe because it eliminates the necessity of bending a flat brake band to the contour of the brake shoe to which it is attached. The shaping of the brake band by the shrinkage of the glue places the cork under additional compression, thus increasing the bond between the cork particles and between the cork and vulcanized fiber. The degree of compression imparted to the cork granules increases with the distance from the backing and is greater at the friction surface than at any other point in the cork layer. In other words, the thicker the cork layer, the greater the compression of the cork granules at the friction surface. This increased compression at the friction surface adds greatly to the life of the brake band and provides a more tenacious gripping surface. The cork granules near the surface of the cork bonded to the vulcanized fiber are compressed to a lesser extent than the cork granules near the friction surface. This lesser degree of compression enables the cork granules inside the band to exercise their natural resiliency to a greater extent than the granules near the friction surface and results in an additional cushioning effect distributed over the entire surface of the brake band.

My brake band provides a positive braking action due to the high co-efiicient of friction of the cork. The natural resilience of the cork eliminates any jarring or vibration of the looms when the brake is applied. This lack of vibration adds greatly to the wear of the looms. Fewer adjustments and expensive repairs to the loom are necessary. The positive braking action reduces the number of seconds in the cloth. The gripping action of my friction facing is so sharp and definite that when the brake is applied for any reason, it stops the loom before the reed hits the cloth. The positive action of the brake band also materially reduces startup marks, running over, cracks, shires, joinings, and imperfections caused by front center stops. My brake lining does not shrink on account of frictional heat, nor does it expand with humidity. Cork is affected less by oil and grease than any other brake lining.

Although the advantages of cork as a brake lining have long been known no brake band has ever been conceived that has successfully utilized the inherent advantages of the cork.

While I have described my brake band as being particularly adapted for use in connection with brakes on textile looms it is to be understood that the invention is not limited to such use but may be used for other purposes of the same general nature.

I claim:

1. A composite lining for brake bands on textile looms comprising a substantially continuous band of hard, flexible, substantially incompressible, nonmetallic material and a friction facing of composition cork adhesively secured thereto throughout substantially its entire area.

2. A composite lining for brake bands on textile looms comprising a hard, flexible, substantially continuous backing of vulcanized fiber and a friction facing of composition cork adhesively secured thereto throughout substantially its entire area.

3. A composite lining for brake bands on textile looms comprising a substantially continuous band of hard, flexible, substantially incompressible, nonmetallic material and a friction facing of composition cork secured thereto throughout substantially its entire area solely by means of an adhesive.

4. A composite lining for brake bands on textile looms comprising a substantially continuous band of hard, flexible, substantially incompressible, nonmetallic material and a3 friction facing of composition cork secured thereto throughout substantially its entire area by means of a casein adhesive.

FREDERIC L. MUNROE. 

